Located along Wawona Road (Route 41) heading south up and out of Yosemite Valley, Tunnel View (also known as "Discovery View") is one of the most famous roadside viewpoints in Yosemite National Park, offering up a classic Ansel Adams view that is one of the best of the park. From the viewing area, you can get a wondrous view of Yosemite Valley several miles in the distance, framed by El Capitan on the left (north) and Bridalveil Fall on the right (south). On a clear day, Half Dome can be seen in the center of the frame with Clouds Rest to the left and Sentinel Dome above on the right.
To get to the viewpoint, simply drive 1.6 south on Wawona Road (Route 41) from the junction with Southside Drive in Yosemite Valley. (You will pass the Bridalveil Fall parking area at the start of the road.) The parking lot has limited spots on both sides of the road and is located just before the road enters Wawona Tunnel (hence the name "tunnel view"). Parking is often hit or miss; sometimes there are several spots, other times it is a traffic jam and mob scene, but with a bit of patience and luck, you can get a spot as turnover is fairly quick.
Be prepared to share the viewpoint with many, many other people, especially at sunset when dozens of photographers with big tripods take over the area. Tour buses frequently stop here as well which adds to the chaos. Tunnel View is also the lower terminus for the Pohono Trail, but very few people will notice the trailhead at the southeast corner of the parking lot.
IMPORTANT: Drive slowly and cautiously through the area as many pedestrians will be crossing the road to get to the viewpoint on the north side of the road. Remember that pedestrians have the right of way.